I would not recommend this approach unless you are really struggling with the game as this will take you longer and you could miss out on the achievements above.

By getting what points you can from the tournaments you can race multiple Time Trial events to bump up your points tally.

Be warned some of the Platinum and Gold times look insane and would probably take longer to master than getting better at the events in the tournament's and focussing on getting Gold in those, but this Time Trial option is available.